This is a bit of a longer post, but it boils down to this simple graphic:

A comparison of the same sentence in English, Japanese, and Korean-

Your goal here is just to notice two things:

The Japanese and Korean translations line up almost perfectly (compare the colors)
The English translation is basically the mirror opposite of the Japanese and Korean translations

If you had those observations and then thought, "Gosh, things would be a lot simpler if I could learn Korean from Japanese instead of learning it from English," then I'd tell you that great minds think alike. This very realization is a big part of the reason that Glossika exists.

Anyway, let's get started.

First, what is "language laddering", anyway?

"Language laddering" refers to the act of using a non-native language to learn another foreign language. More specifically, it's to say that you used your {Native Language A} to learn {Foreign Language B}, and now you're using {Foreign Language B} to learn {Foreign Language C}.

So, it's like a ladder. Get it?

You "step" from language A to language B, and then from language B to language C.

Why not just use my native language?

Well, you could! A lot of people do. Having said that, there are three main reasons to consider learning a foreign language through one of your non-native languages:

It saves time — you're simultaneously reviewing one language while reviewing another language
If your {Foreign Language B} is more similar to {Foreign Language C} than your native language is, that similarity might be worth taking advantage of
The quality of content/resources varies significantly from language to language

—Reason one: it saves time

This one is straightforward. Learning languages gets easier as you go (see the video below for why), but it always takes time.

Learning one or even two languages isn't really such a big deal. At that level, it's just like any other hobby. You can take it slowly over time while going about your life. Learning six or ten languages, though? Now things have gotten serious. I don't think there's a limit to how many languages the brain can keep track of, but there's a hard limit to the amount of hours in a day. If your goal is to be a polyglot — and I mean a real polyglot, not just knowing hi how are you in seven languages — you need to use your time efficiently.

—Reason Two: Concepts transfer better from some languages to other languages

Languages don't exist in isolation — they're grouped into what are called language families. Languages within families tend to be similar, while languages from different families can differ very significantly.

English is in the West Germanic branch of the Indo-European language family, and it's very closely related to languages like German and Dutch. If you want to learn languages other than German or Dutch, however, English likely isn't the theoretical "best" starting point:

If you want to learn French, you'd have an easier time approaching it from another Romance language, such as Spanish or Italian
If you want to learn Cantonese, you'd have an easier time learning it from Mandarin
If you want to learn Azerbaijani, you'd have an easier time learning it from Turkish
(As an aside, you can learn all of those languages on Glossika — click here for a 7-day free trial)

These languages are all from the same branches of the same families. They share a lot of vocabulary, logic, and cultural tendencies. These simlarities greatly smooth out the learning curve inherent to learning a language.

—Reason three: Quality varies from language to language

I mean "quality" here in two ways:

Resources —If you want to learn a smaller language (like Taiwanese Hokkien), there might not be many resources available for it in a "distant" language like English. If you look in Mandarin, however, you'll find many resources!
Explanations — Languages within the same family tend to follow similar logic, or even the same logic. As such, it can be easier to find "practical" explanations for things like grammar in a "closer" language than in a more "distant" language one.

I want to put some emphasis on that second point:

Concepts transfer from language to language. If you know how the subjunctive works in Spanish, you don't need to totally relearn it in French. You just need to figure out how French realizes the subjunctive. That's a much easier task to complete.

To give an example of what I mean — Japanese has a concept called counters. If you want to count something in Japanese, you can't just say three things. You always have to say three {counter} things, as in three loaves of bread. This concept can be hard for English speakers to wrap their heads around, so if you Google Japanese counters, you'll see 3,000-word articles about how counters work.

But if you speak Japanese already and Google how Korean counters work (in Japanese), you'll see something like this instead:

When you want to say ~個 in Japanese, just say ~개 in Korean

That's a bit of an oversimplification, but you get the idea: a three-thousand word English explanation turns into an —eleven— word Japanese explanation. An explanation may not even be necessary because the same except exists in both languages.

How to "ladder" a new language

Thankfully, there's nothing particularly complicated about laddering. You go about learning your target language as you normally would, just using a foreign language instead of your native one. That might mean:

Watching a YouTube course about French in Spanish, rather than English
Using a Japanese textbook to learn Korean, instead of an English one (as an aside, I recommend this textbook)
Using an app, but setting the base language as one of your foreign languages, rather than your native language

We're biased, of course, but laddering languages is super easy on Glossika.

We offer 65 languages, and the way our courses are set up, you can learn pretty much any of our languages from any of our languages. This means you can "ladder" languages like Korean and Japanese or French and Spanish... but it also means you can get access to some very unique combination likes Hindi from Taiwanese Hokkien.

Complacency: A risk of language laddering

When things feel easy, we run the risk of going on autopilot. Becoming complacent. Things will be going smooth, smooth, smooth... and then one day you realize that, unlike French, Spanish employs the subjunctive mood after many things that aren't the word que.

Because the new language felt so easy, you skipped out on some of the importnat infrastructure. Your brain was so firmly locked in "French Mode" that Spanish never really carved out its own space in your head.

A big part of dealing with this comes down to what's known as The Noticing Hypothesis.

...Schmidt posited that a learner cannot continue advancing their language abilities or grasp linguistic features unless they are consciously processing the input, and that what the learner actually notices is called "intake".

Now, I think it's too much to say that you can't improve without consciously noticing "linguistic features". I do think that it's easier to avoid falling into the holes you notice than it is to avoid the ones you don't notice. If you're aware of what's happening in a sentence you encounter, you can file that knowledge away for later — and, importantly, pick up on things that differ from language X to language Y.

How to avoid complacency and get the most out of your routine

As with many things, not just languages, this really comes down to asking good questions and noticing the answers.

As an easy way to get stated, Tim Ferris suggests getting translations of these 8 sentences. I've listed them out below and given samples of some of the kinds of things you might notice.

The apple is red.
This gives you the basic subject-predicate structure.
It is John’s apple.
This shows you how possession works.
I give John the apple.
This has a direct object (the apple) and indirect object (John). Did the form of the word apple change from the first sentence? Did John change from the second sentence?
We give him the apple.
We see a pronoun now (John → him). As with the above sentence, this one also tells you about the most basic logic behind a language's sentence structure: is it subject-verb-object or subject-object-verb?
He gives it to John.
Now we have a direct object pronoun! Does it attach to the verb? Go before or after it?
She gives it to him.
Now we have two object pronouns...
I must give it to him.
This is a test to see if the language is analytic (you stack blocks up) or morphological (you stack a bunch of changes onto one word). The goal is to see if "must" is a separate word, or if rather verbs (like give) have a form that contains the nuance of "must".
I want to give it to her.
Same as above.

If you look at these sentences for a bit, you'll notice that they give you a lot. You get most of the main subject pronouns (I, you, he, she, it, we), some object pronouns (him, her, it), you explore basic present tense verb conjugations, learn about the presence or absence of grammatical case — generally, you get a bunch of wonderful linguistic typology information.

Importantly, this "ask question → seek answer" habit shouldn't stop with the above eight sentences. With every new sentence you see, you should check if (a) it aligns with your current understanding of how the language works, (b) if it challenges that understanding, and/or (c) if it presents you with opportunities to learn something new or reinforce a concept you've been struggling with.

Basically, you want to make sure that you take everything you possibly can out of each sentence.

Got it? Here's a bunch more questions you can ask.

"Language Laddering", or why you might use a foreign language to learn a foreign language